1. Technical Field
The present invention relates to a metal particle dispersion liquid, a method for manufacturing a metal particle dispersion liquid, a method for manufacturing a conductive-film-forming substrate, an electronic device and an electronic apparatus.
2. Related Art
Conductive coatings or films are used for versatile applications, such as electromagnetic shielding for cathode-ray tube monitors, infrared shielding for building materials and automobiles, static shielding for cellular phones and other electronic apparatuses, heat shielding for fogged glass, coating for resin to be conductive, for wiring included in circuit boards and integrated-circuit cards, and for through-holes and circuits.
Examples of methods for making a conductive film include metal vacuum deposition, chemical deposition and ion sputtering. These methods, however, require a complicated process in a vacuum or airtight system and are costly and unsuitable for mass production.
To solve this problem, another method for making a conductive film has been proposed lately that includes applying a metal particle dispersion liquid containing metal particles dispersed in a dispersion medium and heating and burning the dispersion liquid. JP-A-2001-325831 is an example of related art. This method provides a conductive film easily and economically with no process in a vacuum or airtight system required.
The dispersion liquid usually includes a dispersing agent as an additive to disperse metal particles. The dispersing agent needs to be stable in the dispersion liquid but degradable to be removed quickly when the dispersion liquid turns to be a metal film after it is applied.
A highly stable dispersing agent that can increase dispersion is hard to be removed. As a result, it requires a high-temperature burning process to turn the dispersion liquid into a metal film. Moreover, organic components in the agent tend to remain in the metal film, making it difficult to lower the resistance of the film. In contrast, a less stable dispersing agent that can lower the resistance of the film is hard to maintain a sufficient dispersed state of the dispersion liquid. In particular, it is difficult to maintain a stable dispersed state for a long period of time.